Pelvic osteotomy in the neurogenic unstable hip.

Background. The purpose of our study was to evaluate treatment outcome in pelvic osteotomy for neurogenic hip instability, mainly in combination with soft tissue procedures, open reduction in dislocated hips, and proximal femoral osteotomy. Material and methods. 19 patients with neurogenic hip instability were treated from 1996 to 2005, with 29 pelvic osteotomies: 23 for cerebral palsy (15 patients), 5 for meningomyelocoele (3 patients), and 1 for sciatic nerve palsy. There were 19 subluxated and 10 dislocated hips. Results. In the CP patients, 13 patients reported improvement, one patient reported no change, and one patient reported deterioration. In objective assessment, improvement in gross motor function was found in 13 patients, in one patient unchanged, and in one patient walking ability deteriorated. In radiological evaluation, normal or dysplastic hips were achieved in 15 hips (66%). Eight hips (34%) progressively subluxated in follow-up with no redislocation. The subluxations led to repeated surgery in 2 patients. Avascular necrosis of the femoral head occurred in 2 hips (8%). All the MMC and paralytic patients improved in their movement activities. In radiological criteria, all hips were initially improved, but in the follow-up, 3 hips remained dysplastic and 3 hips resubluxated, leading to repeated surgery in one patient. Conclusions. Different types of pelvic osteotomies should be chosen in neuromuscular hip instability according to the hip deformities in order to achieve a stable and congruent hip. The combination with soft tissue release and femoral varus derotation osteotomy offer satisfactory outcomes mainly in the early stage of instability.